The present invention generally relates to lubrication systems. More particularly, the present invention relates to a lubrication system that supplies lubricant from a supply reservoir directly to a lubricant reservoir of a machine.
Industrial machinery requires proper lubrication between contacting parts to insure movement of the parts and to minimize wear of part surfaces. Lubrication also provides a medium for the suspension of particulate matter that could otherwise cause damage to part surfaces as well as seizure of moving parts. Additionally, lubrication facilitates dissipation of heat generated by friction between moving parts. All of these lubricant functions promote proper operation of machinery, prevent machinery failure, and promote longer machinery life. Therefore, a system for providing lubrication to industrial machinery is extremely important.
In industrial manufacturing applications, many types of machinery typically have a lubrication supply system. Many machines are equipped with automatic lubrication supply devices to lubricate mechanisms of the machine. These lubrication systems are typically referred to as xe2x80x9ctotal-loss systemsxe2x80x9d because the lubricant that is pumped throughout the machine is not recovered and recycled through the machine, such as in a closed loop system. After being pumped to the lubrication points within the machine, the lubricant simply flows through effluent conduits, such as channels, to a collection point where this xe2x80x9cwaste lubricantxe2x80x9d is collected in a container, such as a coolant tank of the machine.
These lubrication systems typically utilize a pump to facilitate movement of lubricant through the system. The pump periodically cycles by use of a timer function programmed in a programmable machine controller (PMC). The machine typically includes a lubricant reservoir having a float switch. When the lubricant level in the reservoir falls to a point where the float switch in the reservoir activates, the machine is put into an alarm condition and automatic operation of the machine can no longer be performed. The lubricant in the reservoir must be replenished to restore full automatic function of the machine. A machine operator must fill the reservoir with lubricant and then reset the machine.
Typically, lubricants for re-fill are supplied in 55-gallon drums or 5-gallon pails and stored in a storage area away from the machines. It is usually not practical to keep large drums on the production floor near the machines. Accordingly, when a machine reservoir must be filled, a person has to transport re-fill lubricant from the storage area in a container. In many cases, this container is make-shift and may still contain some content from the original use of the container (e.g., soft-drinks, laundry detergents, other types of lubricant, etc.). Additionally, contaminants such as metal chips, dust, and other matter often collect within the containers as they are stored near the machine. As such, when the container is filled with clean lubricant from the supply container, the lubricant is contaminated. Despite this contamination, the lubricant is poured from these containers into the reservoir of the machine.
Another source of contamination is through the use of a funnel. The reservoirs of the machines are typically located in tight spaces behind access covers or behind the machines. Thus, a funnel is often required when attempting to fill the reservoir. The funnel may have contaminants on its inner surface. Furthermore, the funnel sometimes may not fit directly above the reservoir and therefore must be tilted in order to get the lubricant to flow properly. This tilting can cause the lubricant to be misdirected and spill outside of the machine and onto the floor in the area around the machine, thus creating a hazard.
Typically, lubricant is distributed throughout the machine through steel, plastic, or copper tubing and applied at discharge points through special manifolds. Some of these manifolds can meter the amount of oil applied to surfaces at each cycle of the pump. When contaminated oil flows into these manifolds, the valves, or other metering structures, in the manifolds can malfunction. For example, the valves can be held open by debris in the oil and the metering function cannot work properly. As a result, the machine might start to consume several times the normal amount of lubricant. On the other hand, debris can also stifle lubrication supply to a point where the machine is under-lubricated, which could cause one or more mechanisms within the machine to seize-up and malfunction.
Because the valves on the distribution manifolds cannot usually be cleaned well enough to restore their normal operation, the manifolds are typically replaced. These distribution manifolds can be located deep within the machine and can be extremely difficult to replace. One manifold can cost several hundred dollars to replace. There may be 5-25 such manifolds located throughout the machine. Thus, replacement can be very expensive.
Malfunctioning valves can also cause other problems. The pump of the lubrication system typically has a pressure switch located internally that must activate from a sufficient pressure increase at each cycle of the pump. If the pressure does not sufficiently increase due to improper valve functioning, the machine is put into an alarm condition. The machine can usually be restarted, but is stopped with the alarm condition at each timed cycle of the pump. Typically, this stoppage will occur every 10-30 minutes of automatic operation until the problem is corrected. This results in loss of production time.
An additional loss of production time results when an operator is required to transport lubricant from the storage location to the machine when the reservoir of the machine requires more lubricant. An operator typically has to walk to the lubricant storage location, fill a vessel, walk back to the machine, and then refill the reservoir. In most cases, the low level of the lubricant in the reservoir is not addressed by a machine operator until a xe2x80x9clow lubricant levelxe2x80x9d alarm is generated on the machine. Full and automatic production ceases at that point until the oil is replenished.
With the advent of automatic production cells, this loss of production time can be considerably amplified. Many production cell systems contain robotic units and other moving equipment that can be dangerous to operators and require the entire cell to be contained by a cage. For safety reasons, the cage must be closed in order for the machines to operate automatically. A cell may contain several machines that will generate an alarm due to insufficient lubricant levels at different times. If one machine in the cell generates an alarm, the entire cell might have to be shut down during the lubricant replenishing process. In addition, cells are often interconnected by conveyor systems. Thus, if one cell shuts down, all the subsequent cells might also shut down.
All of these problems and concerns demonstrate a need for an improved lubrication system. The present invention satisfies that need by eliminating the aforementioned problems.
The present invention is a lubrication supply system for one or more self-lubricating machines that provides filling of a lubricant reservoir of the machine directly from a supply reservoir. In one embodiment, the system includes a supply reservoir in fluid communication with a machine reservoir that is fixed to the machine, a transfer mechanism in communication with the supply reservoir and the machine reservoir, and a control system in communication with the transfer mechanism. The control system can be a manual control or an automatic control based on input from a lubricant level indicator in communication with the machine reservoir. In a manual mode, an operator can manually operate the transfer mechanism based on input from the lubricant level indicator. In a preferred automatic control arrangement, the control system controls operation of the transfer mechanism in response to input from a lubricant level indicator when the lubricant level within the machine reservoir either falls below or is filled to a desired lubricant level.
The present invention contemplates embodiments wherein a single supply reservoir is in communication with a plurality of machine reservoirs, and wherein a plurality of supply reservoirs are in communication with a single machine reservoir. One or more transfer mechanisms can be utilized in these embodiments. The system of the present invention also contemplates supplying lubricant directly from a supply reservoir in the form of a container used to ship the lubricant, i.e., an original supply container from the lubricant manufacturer or supplier, thereby eliminating unnecessary transfers into intermediate containers and minimizing potential contamination of the lubricant.
In a preferred embodiment, the system includes a supply container of lubricant in fluid communication with a machine reservoir fixed to the machine, a pump in communication with the supply container and the machine reservoir, and a control system in communication with the machine reservoir and the pump, wherein the control system controls operation of the pump in response to input from a lubricant level indicator to maintain a desired lubricant level within the machine reservoir.
According to a particular aspect of the present invention, the pump can be disposed within the supply reservoir or attached thereto. In a preferred embodiment, the pump is a vacuum-operated piston pump operated by a pneumatic solenoid valve in communication with a pressure source and a control system. The control system determines when to operate the solenoid valve, and thus the pump, through input from a lubricant level indicator.
According to another aspect of the present invention, a connector is adapted to universally connect the supply system of the present invention to a plurality of different reservoir openings associated with machine reservoirs of various types of machines. The connector is preferably a cap that includes a lubricant level indicator.
The present invention also incorporates a method of supplying lubricant to a reservoir of a machine from a supply reservoir of lubricant. The method comprises the steps of transferring lubricant directly from the supply reservoir to the machine reservoir when the lubricant falls below a desired fill level within the machine reservoir, stopping the transfer of lubricant when the lubricant reaches the desired level within the machine reservoir or stopping transfer after a predetermined amount of time expires, and resetting the predetermined amount of time when the lubricant reaches the predetermined level before the predetermined amount of time expires. Additionally, the method can include the step of triggering an indicator when the predetermined amount of time expires. The method also contemplates the step of initially transferring lubricant from the supply reservoir to the machine reservoir to the desired level by temporarily overriding the timing step, thereby preventing stoppage of the initial lubricant transfer when the predetermined amount of time expires before the desired level is reached.
These and many other aspects of the present invention will become apparent from the following detailed description of a particular embodiment of the invention when considered in conjunction with the accompanying drawings.